Rocker switches are currently used notably on dashboards of vehicles such as automobiles, public work or agricultural machines, trucks, or any other type of vehicle. Such a switch comprises at least one switching member which provides a sought-after and determined electrical function.
Standard switches may be actuated by applying a limited force on the rocker in a single direction or in both directions. However, with a simple actuation of this type, the switch may be subject to undesired manipulations, since an accidental stress exerted on the rocker may actuate it.
Consequently, in order to reduce the likelihood of an inadvertent actuation, locking systems have been developed so that the switch cannot be actuated without a combination of two movements.
Locking rocker switches such as the one described in U.S. Pat. No. 4,947,009 are thus known. This 3-position switch has an actuator unit provided with a latch capable of sliding in a direction perpendicular to the plane of symmetry of the rocking. In the central position, the latch prevents any pivoting of the actuator unit. In order to actuate the switch in a given direction, the latch needs to be slid in the opposite direction, in order to free an aperture providing a passage for the actuator member, and then to cause the actuator member to pivot in the relevant direction. Now, handling is not intuitive, because the sliding of the latch and rotation of the actuator member require movements in opposite directions. Moreover, the latch needs to be held with two fingers in order to be able to perform the sequence of movements. Actuation of such a switch therefore requires particular attention from the operator which may distract him/her from driving the vehicle.
U.S. Pat. No. 5,380,964 describes a rocker switch, the locking system of which has improved ergonomics. This switch comprises a casing, an actuator unit and a lever which is used for actuating the switch. The casing includes a stop member of the casing, with which cooperates an abutment surface of the lever, in order to prevent rotation in the direction which corresponds to actuation. Unlocking is carried out by pressing on the lever, by which the abutment surface may pass under the abutment member, which frees the rotation of the lever. Actuation is then carried out by pivoting the lever, the latter being kept pushed in. However, the design of this switch is such that the rotation of the lever in the opposite direction to that of actuation is impossible. This switch therefore is only designed for two positions: a central position and a rocked actuation position, and it is impossible to apply the locking system which it uses, to a three-position switch.
Finally, document DE 44 22 475 describes a three-position rocker switch in which an unlocking button, placed at the centre of the actuator member cooperates with a translationally mobile lock in a direction substantially perpendicular to that of the button. The lock is interposed on the trajectory of the actuator member and is released when a pressure is exerted on the unlocking button.
However, because of its central position, the unlocking button does not provide intuitive unlocking because the lock frees both rocking trajectories simultaneously; pressing on the button therefore does not automatically lead to switching.
Further, this button is not protected and may cause untimely unlocking, particularly critical when the switch is intended for risky controls such as for example a force control for a tractor. Indeed, pressing with a large force may lead to unlocking or to deformation of the shaft which may be detrimental to proper operation of the switch—i.e. blocking of the locking or definitive lack of locking.
One of the objects of the invention is therefore to propose a locking rocker switch which may if necessary be used with a three-position switch, with locking for at least one rocked position or for both of them, and which is provided with an ergonomic and intuitive unlocking system. Another object of the invention is to design a switch for which actuation safety is guaranteed and which may support actuating forces without deteriorating the locking system.